src/libpocketsphinx/acmod.c

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/* -*- c-basic-offset: 4; indent-tabs-mode: nil -*- */
/* ====================================================================
 * Copyright (c) 2008 Carnegie Mellon University.  All rights
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer. 
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * This work was supported in part by funding from the Defense Advanced 
 * Research Projects Agency and the National Science Foundation of the 
 * United States of America, and the CMU Sphinx Speech Consortium.
 *
 * THIS SOFTWARE IS PROVIDED BY CARNEGIE MELLON UNIVERSITY ``AS IS'' AND 
 * ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, 
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL CARNEGIE MELLON UNIVERSITY
 * NOR ITS EMPLOYEES BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * ====================================================================
 *
 */


/* System headers. */
#include <assert.h>

/* SphinxBase headers. */
#include <prim_type.h>
#include <err.h>
#include <cmd_ln.h>
#include <strfuncs.h>
#include <string.h>
#include <byteorder.h>
#include <feat.h>

/* Local headers. */
#include "cmdln_macro.h"
#include "acmod.h"
#include "s2_semi_mgau.h"
#include "ms_mgau.h"

/* Feature and front-end parameters that may be in feat.params */
static const arg_t feat_defn[] = {
    waveform_to_cepstral_command_line_macro(),
    cepstral_to_feature_command_line_macro(),
    CMDLN_EMPTY_OPTION
};

#ifndef WORDS_BIGENDIAN
#define WORDS_BIGENDIAN 1
#endif

static int32 acmod_flags2list(acmod_t *acmod);
static int32 acmod_process_mfcbuf(acmod_t *acmod);

static int
acmod_init_am(acmod_t *acmod)
{
    char const *mdeffn, *tmatfn, *mllrfn;

    /* Read model definition. */
    if ((mdeffn = cmd_ln_str_r(acmod->config, "-mdef")) == NULL) {
        E_ERROR("Must specify -mdef or -hmm\n");
        return -1;
    }

    if ((acmod->mdef = bin_mdef_read(acmod->config, mdeffn)) == NULL) {
        E_ERROR("Failed to read model definition from %s\n", mdeffn);
        return -1;
    }

    /* Read transition matrices. */
    if ((tmatfn = cmd_ln_str_r(acmod->config, "-tmat")) == NULL) {
        E_ERROR("No tmat file specified\n");
        return -1;
    }
    acmod->tmat = tmat_init(tmatfn, acmod->lmath,
                            cmd_ln_float32_r(acmod->config, "-tmatfloor"),
                            TRUE);

    /* Read the acoustic models. */
    if ((cmd_ln_str_r(acmod->config, "-mean") == NULL)
        || (cmd_ln_str_r(acmod->config, "-var") == NULL)
        || (cmd_ln_str_r(acmod->config, "-tmat") == NULL)) {
        E_ERROR("No mean/var/tmat files specified\n");
        return -1;
    }

    E_INFO("Attempting to use SCHMM computation module\n");
    acmod->mgau = s2_semi_mgau_init(acmod);
    if (acmod->mgau) {
        char const *kdtreefn = cmd_ln_str_r(acmod->config, "-kdtree");
        if (kdtreefn)
            s2_semi_mgau_load_kdtree(acmod->mgau, kdtreefn,
                                     cmd_ln_int32_r(acmod->config, "-kdmaxdepth"),
                                     cmd_ln_int32_r(acmod->config, "-kdmaxbbi"));
    }
    else {
        E_INFO("Falling back to general multi-stream GMM computation\n");
        acmod->mgau = ms_mgau_init(acmod->config, acmod->lmath);
    }

    /* If there is an MLLR transform, apply it. */
    if ((mllrfn = cmd_ln_str_r(acmod->config, "-mllr"))) {
        ps_mllr_t *mllr = ps_mllr_read(mllrfn);
        if (mllr == NULL)
            return -1;
        acmod_update_mllr(acmod, mllr);
    }

    return 0;
}

static int
acmod_init_feat(acmod_t *acmod)
{
    acmod->fcb = 
        feat_init(cmd_ln_str_r(acmod->config, "-feat"),
                  cmn_type_from_str(cmd_ln_str_r(acmod->config,"-cmn")),
                  cmd_ln_boolean_r(acmod->config, "-varnorm"),
                  agc_type_from_str(cmd_ln_str_r(acmod->config, "-agc")),
                  1, cmd_ln_int32_r(acmod->config, "-ceplen"));
    if (acmod->fcb == NULL)
        return -1;

    if (cmd_ln_str_r(acmod->config, "-lda")) {
        E_INFO("Reading linear feature transformation from %s\n",
               cmd_ln_str_r(acmod->config, "-lda"));
        if (feat_read_lda(acmod->fcb,
                          cmd_ln_str_r(acmod->config, "-lda"),
                          cmd_ln_int32_r(acmod->config, "-ldadim")) < 0)
            return -1;
    }

    if (cmd_ln_str_r(acmod->config, "-svspec")) {
        int32 **subvecs;
        E_INFO("Using subvector specification %s\n", 
               cmd_ln_str_r(acmod->config, "-svspec"));
        if ((subvecs = parse_subvecs(cmd_ln_str_r(acmod->config, "-svspec"))) == NULL)
            return -1;
        if ((feat_set_subvecs(acmod->fcb, subvecs)) < 0)
            return -1;
    }

    if (cmd_ln_exists_r(acmod->config, "-agcthresh")
        && 0 != strcmp(cmd_ln_str_r(acmod->config, "-agc"), "none")) {
        agc_set_threshold(acmod->fcb->agc_struct,
                          cmd_ln_float32_r(acmod->config, "-agcthresh"));
    }

    if (acmod->fcb->cmn_struct
        && cmd_ln_exists_r(acmod->config, "-cmninit")) {
        char *c, *cc, *vallist;
        int32 nvals;

        vallist = ckd_salloc(cmd_ln_str_r(acmod->config, "-cmninit"));
        c = vallist;
        nvals = 0;
        while (nvals < acmod->fcb->cmn_struct->veclen
               && (cc = strchr(c, ',')) != NULL) {
            *cc = '\0';
            acmod->fcb->cmn_struct->cmn_mean[nvals] = FLOAT2MFCC(atof(c));
            c = cc + 1;
            ++nvals;
        }
        if (nvals < acmod->fcb->cmn_struct->veclen && *c != '\0') {
            acmod->fcb->cmn_struct->cmn_mean[nvals] = FLOAT2MFCC(atof(c));
        }
        ckd_free(vallist);
    }
    return 0;
}

int
acmod_fe_mismatch(acmod_t *acmod, fe_t *fe)
{
    /* Output vector dimension needs to be the same. */
    if (cmd_ln_int32_r(acmod->config, "-ceplen") != fe_get_output_size(fe))
        return TRUE;
    /* Feature parameters need to be the same. */
    /* ... */
    return FALSE;
}

int
acmod_feat_mismatch(acmod_t *acmod, feat_t *fcb)
{
    /* Feature type needs to be the same. */
    if (0 != strcmp(cmd_ln_str_r(acmod->config, "-feat"), feat_name(fcb)))
        return TRUE;
    /* Input vector dimension needs to be the same. */
    if (cmd_ln_int32_r(acmod->config, "-ceplen") != feat_cepsize(fcb))
        return TRUE;
    /* FIXME: Need to check LDA and stuff too. */
    return FALSE;
}

acmod_t *
acmod_init(cmd_ln_t *config, logmath_t *lmath, fe_t *fe, feat_t *fcb)
{
    acmod_t *acmod;
    char const *featparams;

    acmod = ckd_calloc(1, sizeof(*acmod));
    acmod->config = config;
    acmod->lmath = lmath;
    acmod->state = ACMOD_IDLE;

    /* Look for feat.params in acoustic model dir. */
    if ((featparams = cmd_ln_str_r(acmod->config, "-featparams"))) {
        if (cmd_ln_parse_file_r(acmod->config, feat_defn, featparams, FALSE) != NULL) {
            E_INFO("Parsed model-specific feature parameters from %s\n", featparams);
        }
    }

    /* Initialize feature computation. */
    if (fe) {
        if (acmod_fe_mismatch(acmod, fe))
            goto error_out;
        fe_retain(fe);
        acmod->fe = fe;
    }
    else {
        /* Initialize a new front end. */
        cmd_ln_retain(config);
        acmod->fe = fe_init_auto_r(config);
        if (acmod->fe == NULL)
            goto error_out;
    }
    if (fcb) {
        if (acmod_feat_mismatch(acmod, fcb))
            goto error_out;
        feat_retain(fcb);
        acmod->fcb = fcb;
    }
    else {
        /* Initialize a new fcb. */
        if (acmod_init_feat(acmod) < 0)
            goto error_out;
    }

    /* Load acoustic model parameters. */
    if (acmod_init_am(acmod) < 0)
        goto error_out;


    /* The MFCC buffer needs to be at least as large as the dynamic
     * feature window.  */
    acmod->n_mfc_alloc = acmod->fcb->window_size * 2 + 1;
    acmod->mfc_buf = (mfcc_t **)
        ckd_calloc_2d(acmod->n_mfc_alloc, acmod->fcb->cepsize,
                      sizeof(**acmod->mfc_buf));

    /* Feature buffer has to be at least as large as MFCC buffer. */
    acmod->n_feat_alloc = acmod->n_mfc_alloc + cmd_ln_int32_r(config, "-pl_window");
    acmod->feat_buf = feat_array_alloc(acmod->fcb, acmod->n_feat_alloc);

    /* Senone computation stuff. */
    acmod->senone_scores = ckd_calloc(bin_mdef_n_sen(acmod->mdef),
                                                     sizeof(*acmod->senone_scores));
    acmod->senone_active_vec = bitvec_alloc(bin_mdef_n_sen(acmod->mdef));
    acmod->senone_active = ckd_calloc(bin_mdef_n_sen(acmod->mdef),
                                                     sizeof(*acmod->senone_active));
    acmod->log_zero = logmath_get_zero(acmod->lmath);
    acmod->compallsen = cmd_ln_boolean_r(config, "-compallsen");
    return acmod;

error_out:
    acmod_free(acmod);
    return NULL;
}

void
acmod_free(acmod_t *acmod)
{
    if (acmod == NULL)
        return;

    feat_free(acmod->fcb);
    fe_free(acmod->fe);

    if (acmod->mfc_buf)
        ckd_free_2d((void **)acmod->mfc_buf);
    if (acmod->feat_buf)
        feat_array_free(acmod->feat_buf);

    if (acmod->mfcfh)
        fclose(acmod->mfcfh);
    if (acmod->rawfh)
        fclose(acmod->rawfh);

    ckd_free(acmod->senone_scores);
    ckd_free(acmod->senone_active_vec);
    ckd_free(acmod->senone_active);

    if (acmod->mdef)
        bin_mdef_free(acmod->mdef);
    if (acmod->tmat)
        tmat_free(acmod->tmat);
    if (acmod->mgau)
        ps_mgau_free(acmod->mgau);
    if (acmod->mllr)
        ps_mllr_free(acmod->mllr);
    
    ckd_free(acmod);
}

ps_mllr_t *
acmod_update_mllr(acmod_t *acmod, ps_mllr_t *mllr)
{
    if (acmod->mllr)
        ps_mllr_free(acmod->mllr);
    acmod->mllr = mllr;
    ps_mgau_transform(acmod->mgau, mllr);

    return mllr;
}

int
acmod_set_mfcfh(acmod_t *acmod, FILE *logfh)
{
    int rv = 0;

    if (acmod->mfcfh)
        fclose(acmod->mfcfh);
    acmod->mfcfh = logfh;
    fwrite(&rv, 4, 1, acmod->mfcfh);
    return rv;
}

int
acmod_set_rawfh(acmod_t *acmod, FILE *logfh)
{
    if (acmod->rawfh)
        fclose(acmod->rawfh);
    acmod->rawfh = logfh;
    return 0;
}

void
acmod_grow_feat_buf(acmod_t *acmod, int nfr)
{
    mfcc_t ***new_feat_buf;

    new_feat_buf = feat_array_alloc(acmod->fcb, nfr);
    if (acmod->n_feat_frame || acmod->grow_feat) {
        memcpy(new_feat_buf[0][0], acmod->feat_buf[0][0],
               (acmod->n_feat_alloc
                * feat_dimension(acmod->fcb)
                * sizeof(***acmod->feat_buf)));
    }
    feat_array_free(acmod->feat_buf);
    acmod->feat_buf = new_feat_buf;
    acmod->n_feat_alloc = nfr;
}

int
acmod_set_grow(acmod_t *acmod, int grow_feat)
{
    int tmp = acmod->grow_feat;
    acmod->grow_feat = grow_feat;

    /* Expand feat_buf to a reasonable size to start with. */
    if (grow_feat && acmod->n_feat_alloc < 128)
        acmod_grow_feat_buf(acmod, 128);

    return tmp;
}

int
acmod_start_utt(acmod_t *acmod)
{
    fe_start_utt(acmod->fe);
    acmod->state = ACMOD_STARTED;
    acmod->n_mfc_frame = 0;
    acmod->n_feat_frame = 0;
    acmod->mfc_outidx = 0;
    acmod->feat_outidx = 0;
    acmod->output_frame = 0;
    acmod->senscr_frame = -1;
    acmod->n_senone_active = 0;
    acmod->mgau->frame_idx = 0;
    return 0;
}

int
acmod_end_utt(acmod_t *acmod)
{
    int32 nfr = 0;

    acmod->state = ACMOD_ENDED;
    if (acmod->n_mfc_frame < acmod->n_mfc_alloc) {
        int inptr;
        /* Where to start writing them (circular buffer) */
        inptr = (acmod->mfc_outidx + acmod->n_mfc_frame) % acmod->n_mfc_alloc;
        /* nfr is always either zero or one. */
        fe_end_utt(acmod->fe, acmod->mfc_buf[inptr], &nfr);
        acmod->n_mfc_frame += nfr;
        /* Process whatever's left, and any leadout. */
        if (nfr)
            nfr = acmod_process_mfcbuf(acmod);
    }
    if (acmod->mfcfh) {
        int32 outlen, rv;
        outlen = (ftell(acmod->mfcfh) - 4) / 4;
        if (!WORDS_BIGENDIAN)
            SWAP_INT32(&outlen);
        /* Try to seek and write */
        if ((rv = fseek(acmod->mfcfh, 0, SEEK_SET)) == 0) {
            fwrite(&outlen, 4, 1, acmod->mfcfh);
        }
        fclose(acmod->mfcfh);
        acmod->mfcfh = NULL;
    }
    if (acmod->rawfh) {
        fclose(acmod->rawfh);
        acmod->rawfh = NULL;
    }

    return nfr;
}

static int
acmod_log_mfc(acmod_t *acmod,
              mfcc_t **cep, int n_frames)
{
    int i, n;
    int32 *ptr = (int32 *)cep[0];

    n = n_frames * feat_cepsize(acmod->fcb);
    /* Swap bytes. */
    if (!WORDS_BIGENDIAN) {
        for (i = 0; i < (n * sizeof(mfcc_t)); ++i) {
            SWAP_INT32(ptr + i);
        }
    }
    /* Write features. */
    if (fwrite(cep[0], sizeof(mfcc_t), n, acmod->mfcfh) != n) {
        E_ERROR_SYSTEM("Failed to write %d values to log file", n);
    }

    /* Swap them back. */
    if (!WORDS_BIGENDIAN) {
        for (i = 0; i < (n * sizeof(mfcc_t)); ++i) {
            SWAP_INT32(ptr + i);
        }
    }
    return 0;
}

static int
acmod_process_full_cep(acmod_t *acmod,
                       mfcc_t ***inout_cep,
                       int *inout_n_frames)
{
    int32 nfr;

    /* Write to log file. */
    if (acmod->mfcfh)
        acmod_log_mfc(acmod, *inout_cep, *inout_n_frames);

    /* Resize feat_buf to fit. */
    if (acmod->n_feat_alloc < *inout_n_frames) {
        feat_array_free(acmod->feat_buf);
        acmod->feat_buf = feat_array_alloc(acmod->fcb, *inout_n_frames);
        acmod->n_feat_alloc = *inout_n_frames;
        acmod->n_feat_frame = 0;
        acmod->feat_outidx = 0;
    }
    /* Make dynamic features. */
    nfr = feat_s2mfc2feat_live(acmod->fcb, *inout_cep, inout_n_frames,
                               TRUE, TRUE, acmod->feat_buf);
    acmod->n_feat_frame = nfr;
    assert(acmod->n_feat_frame <= acmod->n_feat_alloc);
    *inout_cep += *inout_n_frames;
    *inout_n_frames = 0;
    return nfr;
}

static int
acmod_process_full_raw(acmod_t *acmod,
                       int16 const **inout_raw,
                       size_t *inout_n_samps)
{
    int32 nfr, ntail;
    mfcc_t **cepptr;

    /* Write to logging file if any. */
    if (acmod->rawfh)
        fwrite(*inout_raw, 2, *inout_n_samps, acmod->rawfh);
    /* Resize mfc_buf to fit. */
    if (fe_process_frames(acmod->fe, NULL, inout_n_samps, NULL, &nfr) < 0)
        return -1;
    if (acmod->n_mfc_alloc < nfr + 1) {
        ckd_free_2d(acmod->mfc_buf);
        acmod->mfc_buf = ckd_calloc_2d(nfr + 1, fe_get_output_size(acmod->fe),
                                       sizeof(**acmod->mfc_buf));
        acmod->n_mfc_alloc = nfr + 1;
    }
    acmod->n_mfc_frame = 0;
    acmod->mfc_outidx = 0;
    fe_start_utt(acmod->fe);
    if (fe_process_frames(acmod->fe, inout_raw, inout_n_samps,
                          acmod->mfc_buf, &nfr) < 0)
        return -1;
    fe_end_utt(acmod->fe, acmod->mfc_buf[nfr], &ntail);
    nfr += ntail;

    cepptr = acmod->mfc_buf;
    nfr = acmod_process_full_cep(acmod, &cepptr, &nfr);
    acmod->n_mfc_frame = 0;
    return nfr;
}

static int32
acmod_process_mfcbuf(acmod_t *acmod)
{
    mfcc_t **mfcptr;
    int32 ncep;

    ncep = acmod->n_mfc_frame;
    /* Also do this in two parts because of the circular mfc_buf. */
    if (acmod->mfc_outidx + ncep > acmod->n_mfc_alloc) {
        int32 ncep1 = acmod->n_mfc_alloc - acmod->mfc_outidx;
        int saved_state = acmod->state;

        /* Make sure we don't end the utterance here. */
        if (acmod->state == ACMOD_ENDED)
            acmod->state = ACMOD_PROCESSING;
        mfcptr = acmod->mfc_buf + acmod->mfc_outidx;
        ncep1 = acmod_process_cep(acmod, &mfcptr, &ncep1, FALSE);
        /* It's possible that not all available frames were filled. */
        ncep -= ncep1;
        acmod->n_mfc_frame -= ncep1;
        acmod->mfc_outidx += ncep1;
        acmod->mfc_outidx %= acmod->n_mfc_alloc;
        /* Restore original state (could this really be the end) */
        acmod->state = saved_state;
    }
    mfcptr = acmod->mfc_buf + acmod->mfc_outidx;
    ncep = acmod_process_cep(acmod, &mfcptr, &ncep, FALSE);
    acmod->n_mfc_frame -= ncep;
    acmod->mfc_outidx += ncep;
    acmod->mfc_outidx %= acmod->n_mfc_alloc;
    return ncep;
}

int
acmod_process_raw(acmod_t *acmod,
                  int16 const **inout_raw,
                  size_t *inout_n_samps,
                  int full_utt)
{
    int32 ncep;

    /* If this is a full utterance, process it all at once. */
    if (full_utt)
        return acmod_process_full_raw(acmod, inout_raw, inout_n_samps);

    /* Write to logging file if any. */
    if (acmod->rawfh)
        fwrite(*inout_raw, 2, *inout_n_samps, acmod->rawfh);
    /* Append MFCCs to the end of any that are previously in there
     * (in practice, there will probably be none) */
    if (inout_n_samps && *inout_n_samps) {
        int inptr;

        /* Total number of frames available. */
        ncep = acmod->n_mfc_alloc - acmod->n_mfc_frame;
        /* Where to start writing them (circular buffer) */
        inptr = (acmod->mfc_outidx + acmod->n_mfc_frame) % acmod->n_mfc_alloc;

        /* Write them in two (or more) parts if there is wraparound. */
        while (inptr + ncep > acmod->n_mfc_alloc) {
            int32 ncep1 = acmod->n_mfc_alloc - inptr;
            if (fe_process_frames(acmod->fe, inout_raw, inout_n_samps,
                                  acmod->mfc_buf + inptr, &ncep1) < 0)
                return -1;
            /* ncep1 now contains the number of frames actually
             * processed.  This is a good thing, but it means we
             * actually still might have some room left at the end of
             * the buffer, hence the while loop.  Unfortunately it
             * also means that in the case where we are really
             * actually done, we need to get out totally, hence the
             * goto. */
            acmod->n_mfc_frame += ncep1;
            ncep -= ncep1;
            inptr += ncep1;
            inptr %= acmod->n_mfc_alloc;
            if (ncep1 == 0)
                goto alldone;
        }
        assert(inptr + ncep <= acmod->n_mfc_alloc);
        if (fe_process_frames(acmod->fe, inout_raw, inout_n_samps,
                              acmod->mfc_buf + inptr, &ncep) < 0)
            return -1;
        acmod->n_mfc_frame += ncep;
    alldone:
        ;
    }

    /* Hand things off to acmod_process_cep. */
    return acmod_process_mfcbuf(acmod);
}

int
acmod_process_cep(acmod_t *acmod,
                  mfcc_t ***inout_cep,
                  int *inout_n_frames,
                  int full_utt)
{
    int32 nfeat, ncep, inptr;
    int orig_n_frames;

    /* If this is a full utterance, process it all at once. */
    if (full_utt)
        return acmod_process_full_cep(acmod, inout_cep, inout_n_frames);

    /* Write to log file. */
    if (acmod->mfcfh)
        acmod_log_mfc(acmod, *inout_cep, *inout_n_frames);

    /* Maximum number of frames we're going to generate. */
    orig_n_frames = ncep = nfeat = *inout_n_frames;

    /* FIXME: This behaviour isn't guaranteed... */
    if (acmod->state == ACMOD_ENDED)
        nfeat += feat_window_size(acmod->fcb);
    else if (acmod->state == ACMOD_STARTED)
        nfeat -= feat_window_size(acmod->fcb);

    /* Clamp number of features to fit available space. */
    if (nfeat > acmod->n_feat_alloc - acmod->n_feat_frame) {
        /* Grow it as needed - we have to grow it at the end of an
         * utterance because we can't return a short read there. */
        if (acmod->grow_feat || acmod->state == ACMOD_ENDED)
            acmod_grow_feat_buf(acmod, acmod->n_feat_alloc + nfeat);
        else
            ncep -= (nfeat - (acmod->n_feat_alloc - acmod->n_feat_frame));
    }

    /* Where to start writing in the feature buffer. */
    if (acmod->grow_feat) {
        /* Grow to avoid wraparound if grow_feat == TRUE. */
        inptr = acmod->feat_outidx + acmod->n_feat_frame;
        while (inptr + nfeat > acmod->n_feat_alloc)
            acmod_grow_feat_buf(acmod, acmod->n_feat_alloc * 2);
    }
    else {
        inptr = (acmod->feat_outidx + acmod->n_feat_frame) % acmod->n_feat_alloc;
    }

    /* Write them in two parts if there is wraparound. */
    if (inptr + nfeat > acmod->n_feat_alloc) {
        int32 ncep1 = acmod->n_feat_alloc - inptr;
        int saved_state = acmod->state;

        /* Make sure we don't end the utterance here. */
        if (acmod->state == ACMOD_ENDED)
            acmod->state = ACMOD_PROCESSING;
        nfeat = feat_s2mfc2feat_live(acmod->fcb, *inout_cep,
                                     &ncep1,
                                     (acmod->state == ACMOD_STARTED),
                                     (acmod->state == ACMOD_ENDED),
                                     acmod->feat_buf + inptr);
        if (nfeat < 0)
            return -1;
        /* Move the output feature pointer forward. */
        acmod->n_feat_frame += nfeat;
        assert(acmod->n_feat_frame <= acmod->n_feat_alloc);
        inptr += nfeat;
        inptr %= acmod->n_feat_alloc;
        /* Move the input feature pointers forward. */
        *inout_n_frames -= ncep1;
        *inout_cep += ncep1;
        ncep -= ncep1;
        /* Restore original state (could this really be the end) */
        acmod->state = saved_state;
    }

    nfeat = feat_s2mfc2feat_live(acmod->fcb, *inout_cep,
                                 &ncep,
                                 (acmod->state == ACMOD_STARTED),
                                 (acmod->state == ACMOD_ENDED),
                                 acmod->feat_buf + inptr);
    if (nfeat < 0)
        return -1;
    acmod->n_feat_frame += nfeat;
    assert(acmod->n_feat_frame <= acmod->n_feat_alloc);
    /* Move the input feature pointers forward. */
    *inout_n_frames -= ncep;
    *inout_cep += ncep;
    if (acmod->state == ACMOD_STARTED)
        acmod->state = ACMOD_PROCESSING;
    return orig_n_frames - *inout_n_frames;
}

int
acmod_process_feat(acmod_t *acmod,
                   mfcc_t **feat)
{
    int i, inptr;

    if (acmod->n_feat_frame == acmod->n_feat_alloc) {
        if (acmod->grow_feat)
            acmod_grow_feat_buf(acmod, acmod->n_feat_alloc * 2);
        else
            return 0;
    }

    inptr = (acmod->feat_outidx + acmod->n_feat_frame) % acmod->n_feat_alloc;
    for (i = 0; i < feat_dimension1(acmod->fcb); ++i)
        memcpy(acmod->feat_buf[inptr][i],
               feat[i], feat_dimension2(acmod->fcb, i) * sizeof(**feat));
    ++acmod->n_feat_frame;
    assert(acmod->n_feat_frame <= acmod->n_feat_alloc);

    return 1;
}

int
acmod_rewind(acmod_t *acmod)
{
    /* If the feature buffer is circular, this is not possible. */
    if (acmod->output_frame > acmod->n_feat_alloc)
        return -1;

    /* Frames consumed + frames available */
    acmod->n_feat_frame = acmod->output_frame + acmod->n_feat_frame;

    /* Reset output pointers. */
    acmod->feat_outidx = 0;
    acmod->output_frame = 0;
    acmod->senscr_frame = -1;
    acmod->mgau->frame_idx = 0;

    return 0;
}

int
acmod_advance(acmod_t *acmod)
{
    /* Advance the output pointers. */
    if (++acmod->feat_outidx == acmod->n_feat_alloc)
        acmod->feat_outidx = 0;
    --acmod->n_feat_frame;
    ++acmod->mgau->frame_idx;

    return ++acmod->output_frame;
}

int16 const *
acmod_score(acmod_t *acmod,
            int *inout_frame_idx)
{
    int frame_idx, feat_idx, n_backfr;

    /* Calculate the absolute frame index to be scored. */
    if (inout_frame_idx == NULL)
        frame_idx = acmod->output_frame;
    else if (*inout_frame_idx < 0)
        frame_idx = acmod->output_frame + 1 + *inout_frame_idx;
    else
        frame_idx = *inout_frame_idx;

    /* Check to make sure features are available for the requested frame index. */
    n_backfr = acmod->n_feat_alloc - acmod->n_feat_frame;
    if (frame_idx < 0 || acmod->output_frame - frame_idx > n_backfr) {
        E_ERROR("Frame %d outside queue of %d frames, %d alloc (%d > %d), cannot score\n",
                frame_idx, acmod->n_feat_frame, acmod->n_feat_alloc,
                acmod->output_frame - frame_idx, n_backfr);
        return NULL;
    }

    /* If all senones are being computed then we can reuse existing scores. */
    if (acmod->compallsen && frame_idx == acmod->senscr_frame)
        return acmod->senone_scores;

    /* Build active senone list. */
    acmod_flags2list(acmod);

    /* Get the index in feat_buf of the frame to be scored. */
    feat_idx = ((acmod->feat_outidx + frame_idx - acmod->output_frame)
                % acmod->n_feat_alloc);
    if (feat_idx < 0) feat_idx += acmod->n_feat_alloc;

    /* Generate scores for the next available frame */
    ps_mgau_frame_eval(acmod->mgau,
                       acmod->senone_scores,
                       acmod->senone_active,
                       acmod->n_senone_active,
                       acmod->feat_buf[feat_idx],
                       frame_idx,
                       acmod->compallsen);

    if (inout_frame_idx)
        *inout_frame_idx = frame_idx;
    acmod->senscr_frame = frame_idx;

    return acmod->senone_scores;
}

int
acmod_best_score(acmod_t *acmod, int *out_best_senid)
{
    int i, best;

    best = WORST_SCORE;
    if (acmod->compallsen) {
        for (i = 0; i < bin_mdef_n_sen(acmod->mdef); ++i) {
            if (acmod->senone_scores[i] BETTER_THAN best) {
                best = acmod->senone_scores[i];
                *out_best_senid = i;
            }
        }
    }
    else {
        int16 *senscr;
        senscr = acmod->senone_scores;
        for (i = 0; i < acmod->n_senone_active; ++i) {
            senscr += acmod->senone_active[i];
            if (*senscr BETTER_THAN best) {
                best = *senscr;
                *out_best_senid = i;
            }
        }
    }
    return best;
}


void
acmod_clear_active(acmod_t *acmod)
{
    bitvec_clear_all(acmod->senone_active_vec, bin_mdef_n_sen(acmod->mdef));
    acmod->n_senone_active = 0;
}

#define MPX_BITVEC_SET(a,h,i)                                   \
    if (hmm_mpx_ssid(h,i) != BAD_SSID)                          \
        bitvec_set((a)->senone_active_vec, hmm_mpx_senid(h,i))
#define NONMPX_BITVEC_SET(a,h,i)                                        \
    bitvec_set((a)->senone_active_vec,                                  \
               hmm_nonmpx_senid(h,i))

void
acmod_activate_hmm(acmod_t *acmod, hmm_t *hmm)
{
    int i;

    if (hmm_is_mpx(hmm)) {
        switch (hmm_n_emit_state(hmm)) {
        case 5:
            MPX_BITVEC_SET(acmod, hmm, 4);
            MPX_BITVEC_SET(acmod, hmm, 3);
        case 3:
            MPX_BITVEC_SET(acmod, hmm, 2);
            MPX_BITVEC_SET(acmod, hmm, 1);
            MPX_BITVEC_SET(acmod, hmm, 0);
            break;
        default:
            for (i = 0; i < hmm_n_emit_state(hmm); ++i) {
                MPX_BITVEC_SET(acmod, hmm, i);
            }
        }
    }
    else {
        switch (hmm_n_emit_state(hmm)) {
        case 5:
            NONMPX_BITVEC_SET(acmod, hmm, 4);
            NONMPX_BITVEC_SET(acmod, hmm, 3);
        case 3:
            NONMPX_BITVEC_SET(acmod, hmm, 2);
            NONMPX_BITVEC_SET(acmod, hmm, 1);
            NONMPX_BITVEC_SET(acmod, hmm, 0);
            break;
        default:
            for (i = 0; i < hmm_n_emit_state(hmm); ++i) {
                NONMPX_BITVEC_SET(acmod, hmm, i);
            }
        }
    }
}

static int32
acmod_flags2list(acmod_t *acmod)
{
    int32 w, l, n, b, total_dists, total_words, extra_bits;
    bitvec_t *flagptr;

    total_dists = bin_mdef_n_sen(acmod->mdef);
    if (acmod->compallsen) {
        acmod->n_senone_active = total_dists;
        return total_dists;
    }
    total_words = total_dists / BITVEC_BITS;
    extra_bits = total_dists % BITVEC_BITS;
    w = n = l = 0;
    for (flagptr = acmod->senone_active_vec; w < total_words; ++w, ++flagptr) {
        if (*flagptr == 0)
            continue;
        for (b = 0; b < BITVEC_BITS; ++b) {
            if (*flagptr & (1UL << b)) {
                int32 sen = w * BITVEC_BITS + b;
                int32 delta = sen - l;
                /* Handle excessive deltas "lossily" by adding a few
                   extra senones to bridge the gap. */
                while (delta > 255) {
                    acmod->senone_active[n++] = 255;
                    delta -= 255;
                }
                acmod->senone_active[n++] = delta;
                l = sen;
            }
        }
    }

    for (b = 0; b < extra_bits; ++b) {
        if (*flagptr & (1UL << b)) {
            int32 sen = w * BITVEC_BITS + b;
            int32 delta = sen - l;
            /* Handle excessive deltas "lossily" by adding a few
               extra senones to bridge the gap. */
            while (delta > 255) {
                acmod->senone_active[n++] = 255;
                delta -= 255;
            }
            acmod->senone_active[n++] = delta;
            l = sen;
        }
    }

    acmod->n_senone_active = n;
    E_DEBUG(1, ("acmod_flags2list: %d active in frame %d\n",
                acmod->n_senone_active, acmod->output_frame));
    return n;
}

---